Test run "hangs" at startup with invalid code

[DanTup]

import 'package:test/test.dart';

main() {
  test('slow', () async {
    print('starting...');
    await Future<void>.delayed(const Duration(seconds: 5));
  }, timeout: const Timeout.factor(10));
}

When I try to run this code, it fails with this error:

However, if I try to Debug it (both runs use the CodeLens on the main function), it just hangs with no error:

[DanTup]

In launch.json I had --enable-experiment=records from some testing, but it's test with "templateFor": "test" and is being passed to test. The launch is then failing with:

Could not find an option named "enable-experiment".

Usage: dart test [files or directories...]

-h, --help                            Show this usage information.
    --version                         Show the package:test version.

And for some reason we're parsing usage: as a URI we need to convert. When we send this to the VM, the isolate seems to exit.

This may or may not be related, but:

• we shouldn't be trying to convert usage:
• we perhaps should not see an isolate terminate when we do this was actually exiting because the process didn't start
• the error output above should be visible to the user

[DanTup]

With fix:

[DanTup]

https://dart-review.googlesource.com/c/sdk/+/279513

[DanTup]

Fixed by dart-lang/sdk@589876b.